According to WHO statistics on blood safety, 80 percent of the world's population has access to 20 percent of the world's safe blood supply. However, more than 20 percent (13,000,000 units) of the world blood supply is not tested for the three major transfusion transmissible infections: HIV, HBV and HCV. Transfusion or injection of unsafe blood accounts for 8-16 million hepatitis B virus infections, 2.3-4.7 million hepatitis C virus infections, and 80,000-1 60,000 HIV infections each year. The problem is especially severe in resource-poor countries where the availability of safe blood clearly needs to be increased. If inexpensive, rapid, improved dipsticks with sensitivity comparable to EIA were developed for blood screening, it would greatly improve the safety of the blood supply in developing countries. In addition, a Triplex test format capable of detecting simultaneously low levels of HBsAg or antibodies to HIV or HCV would provide blood banks in resource-limited settings with the means for screening all three ma]or viral markers in a format adapted to local settings and resources. The aim of this Phase I work is to develop a working duplex dipstick as proof of principle for the Triplex assay format planned for Phase II. Thus at the end of Phase I, the working duplex dipstick will have demonstrated that HbsAg and anti-HIV p24 antibodies can be simultaneously detected from a single sample using one dipstick. We propose that this duplex test could then be expanded into a Triplex test and used as the initial step of blood screening in resource-poor, high prevalence countries. The associated second step is to use a test detecting specifically HBsAg or HIV or HCV (Reflex) to identify the agent responsible for the initial test result.